1. Field of the Invention
The present invention relates to a ray tracing method, and in particular, a ray tracing method for an automobile headlight or the like.
2. Description of the Related Art
Conventionally, in the lamp of an automobile headlight or the like, first, a reflector which reflects light of a light source is formed. Thereafter, a ray is traced with the light source disposed at a predetermined position, and the position of the focal point of the lamp of the headlight or the like and the illuminance of the illuminated surface are computed (see "Journal of the Illuminating Engineering Institute of Japan", Vol. 76, No. 12, pp. 647-655).
However, because this method does not take into consideration the existence of a lens disposed in front of the light source, plural reflections or refractions between the lens and the reflector cannot be analyzed, and the illuminance cannot be computed accurately. Further, because the light is not considered from the point of view of spectrooptics, the color state of the lamp (more specifically, the perceived color of the lamp which is due to the effects of reflection and refraction caused by the configuration of the reflector and the cut configuration of the lens) cannot be analyzed accurately.